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  • Aluminium-induced changes of fusion pore properties attenuate prolactin secretion in rat pituitary lactotrophs
    Costa Calejo, Ana-Isabel ...
    Hormone secretion is mediated by Ca(2+)-regulated exocytosis. The key step of this process consists of the merger of the vesicle and the plasma membranes, leading to the formation of a fusion pore. ... This is an aqueous channel through which molecules stored in the vesicle lumen exit into the extracellular space on stimulation. Here we studied the effect of sub-lethal dose of aluminium onprolactin secretion in isolated rat pituitary lactotrophs with an enzyme immunoassay and by monitoring electrophysiologically the interaction of a single vesicle with the plasma membrane in real time, by monitoring membrane capacitance. After 24-h exposure to sub-lethal AlCl(3) (30 muM), the secretionof prolactin was reduced by 14+/-8% and 46+/-11% under spontaneous and K(+)-stimulated conditions, respectively. The frequency of unitary exocytotic events, recorded by the high-resolution patch-clamp monitoring of membrane capacitance, a parameter linearly related to the membrane area, underspontaneous and stimulated conditions, was decreased in aluminium-treatedcells. Moreover, while the fusion pore dwell-time was increased in the presence of aluminium, the fusion pore conductance, a measure of fusion pore diameter, was reduced, both under spontaneous and stimulated conditions. These results suggest that sub-lethal aluminium concentrations reduce prolactin secretion downstream of the stimulus secretion coupling by decreasing the frequency of unitary exocytotic events and by stabilizing the fusion pore diameter to a value smaller than prolactin molecule, thus preventing its discharge into the extracellular space.
    Vir: Neuroscience. - ISSN 0306-4522 (Vol. 201, 2012, str. 57-66)
    Vrsta gradiva - članek, sestavni del
    Leto - 2012
    Jezik - angleški
    COBISS.SI-ID - 29371609
    DOI

vir: Neuroscience. - ISSN 0306-4522 (Vol. 201, 2012, str. 57-66)
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